Transmission system



D. G. BLATTNER TRANSMIS S ION SYSTEM 'June 19, v1923.

Filed June 24 //7 Ven/0H @aV/a G. 5767/291611 y Maf.

Patented June 19, 1923.

t 1,459,434 TES PATENT OFFICE.

DAVID G. BLATTNER, 0F NEW YORK, N. Y., ASSIGNOR TO WESTERN ELECTRIC COM- PANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TRANSMISSION SYSTEM.

Application led June 24, 1919. Serifal No. 306,324.

sitated thereby but also since the phenomena may occur due to the operation of this means. It is therefore desirable to provide means which will automatically prevent the occurrence of the phenomena and which is independent of the observer.

One system of this nature which has been used successfully in marine and submarine detection Work employs a pair of transmitters of this character located at separate fixed positions To all 'whom it may concern.'

Be it known that I, DAVID G. BLATTNER, a citizen of the United States, residingl at New York, in the county of New York, State of New York, have invented certain new and useful Improvements in Transmission Systems, of which the following is a full,I clear, concise, and exact description.

This invention relates to transmission systems and more particularly to systems in which transmitters are used which contain finely comminuted resistance varying material. f K

In such systems it is desirable to .elimich nate, as much as may be possible, the s0- called pac 'ng and cohering of the particles of the resistance varying material which phenomena deleteriously affect the changes produced by the transmitter in the conditions of an associated electrical circuit.

In some systems employed in the detection and location of marine or submarine vessels transmitters of this character are used, and since the transmitters in such systems must respond to very feeble mechanical vibrations propagated through the water from a distant source, which vibrations vary over a wide range of frequencies, it is essential that the transmitters be maintained at a high degree of eiiiciencyand also at a high degree of stability at all times. It' is therefore desirable to eliminate the effects upon the response ofcsuch transmitters due to extraneous or variable conditions which may be impressed upon the operating circuit thereof.

In transmitters of this nature employed in connection with the ordinary telephone, it is possible for the user to dislodge the packed or cohered resistance varying particles by tapping or shaking the transmitter itself and thus cause them to assume their normal operative positions. However, due to thefact that in systems for the detection of marine or submarine vessels the transmitters are usually submerged andare located at considerable distances from the o erver, such methods cannot be followed -in such cases.

eretofore it has been roposed in sysioy observer conmeans located perform this such means being operated before of observation, but such methods proven entirely satisfactory not the loss of valuable time neoesformand accurate4 as may is to be accura 80 `impair the accuracy of the binaural observation. By experimentation and study, it has been determined that these coheringffects are principally due to sudden surges i -of current through the resistance varying material which cause the particles thereof to assume a somewhat permanent arrangement the transmitters do not readily respond to received vibrations and the effects are practically independent of the amount jcurrent fiowmof through the material. eretofore, it has been proposed to eliminatel these surges by synchronously closing or opening both conductors.` of the operating circuits of the transmitters and by insuring that the circuits are not closed oropened adjacent the transmitter. However, it has not been possible by these means to entirely prevent the occurrence of the phenomenon e'specially when caused by other currents which mayfbe impressed upon such circuit lfor other purposes.V

It is an object of this invention to provide 110 tems of this nature to emp trolled electrically operated adjacent the transmitter to function, each series have. not

only due to los ` tion A, is included in the clearly appear accordance with an impedance is -included in each conductor of the operating circuit ofthe transmitter which serves to modify a current surge therethrough before it reaches the' transmitter, the impedances in the two conductors being soiproportioned and mutually related as to introduce no appreciable impedances into the normal operating circuit of the transmitter. More specifically, an impedance coil comprising two equal windings placed on the same core, in such relation r'as to be inductively balanced, is employed, onewinding being included in each conductor of the circuit adjacent the associated terminal of the transmitter.

This and other features of the invention not specifically mentioned abovewill more from the following specification andthe annexed drawing, inwhich Fig. 1 illustrates one embodiment of the invention, as applied to a binaural system for the detection and location of submarines, while Fig. 2vshows in a simplified form, theop erating circuit of one detectingr transmitter, and Fig. 3 diagrammatically illustrates the change in wave form of a current surge which is caused by the modifying means of the invention.

1 of the drawing, an observers station which may be located at some convenient point on `the shore is provided with a sending or selecting key 1, controlling a reversing Referring to Fi relay 2 for ini pressing current impulses of reversed polarity upon a phantom circuit comprising side circuits including conductors 3-4 and 5-6, and suitable simplexing coils 7 to 10, inelusive, leading to the several detecting stations of the system, only one of which, station B, is shown, the others having been omitted for the sake of clearness. A selector 11, which may be of any suitable step# by-step type adapted to individually cause its switch arm 12 to engage a contact 13, thereby bridging relay 14 across the phantom circuit upon receiving a predetermined series of closely succeeding reverse current impulses from the observing staplantom circuit The selectively operated cirdevice disclosed in application, Serial No. 98,384, filed May. 18, 1916 by Joseph C. Field, may be used to advanta-ge in this connection. The relay 14 controls the connection of vibration. detectors 15' and 16 across the conductors 3-4 and 5 6, respectively. These detectors may be of any suitable type employing finely at station B. cuit controlling ceivers 21 and 22 which may be of' any' usual type in series with condensers 23 and 24, respectively, in bridged relation to the physical circuits 3-4 and 56, respectively.

The sounds produced by receiver 21 are conveyed to ear piece 31 through serially interconnected air tubes 25, 27 and 29, while the sounds produced by receiver 22 are conveyed to ear piece 32 through serially interconnected air tubes 26, 28 and 30. The effective lengths of the adjustable air tubes 27 and 28 are relatively varied by the shifting of a movable stop-member 33 in response to the rotation of the hand' wheel 34, the angular position of such member being indicated by a pointer 35 carried by the hand wheel in relation to an associated scale.

In Fig. 2 the operating circuit of detector 16 when associated with the side circuit including the conductors 5 and 6 is diagrammatically shown in a simplified form. Condensers 42 to 47, inclusive, represent the capacitance existing between the respective line conductors 5--6 and ground, while the coils 49 and 50 represent the resistances existing between the various points at which such capacitances are located. Such capacitances andv resistances are usually distributed along the cable containing the conductors 5 and 6 but for the purpose of a clear understanding of the invention, may

be considered as occurring at certain specific points.

In Fig. 3 a curve X illustrates the Wave form assumed by the current in charging a condenser and represents one of the common forms of momentary surges encountered inthe operation of -the system shown in Figs. 1 and 2, while a curve Y illustrates the modified wave form assumed by such surge with a winding of impedance coil 37 included in the circuit.- l

It is thought that the invention may be more clearly understood from the following description of the operation ofy the system shownin the drawing.

Referring more particularly to Fig. 1 and assuming that it is eration of the detectors 15 and 16 at station B in response to some source of vibration, the

observer actuates and releases keyv 1 to cause the relay 2 to transmit a predetermined numdesired to observe the opsociated with the system tubes 26, 28 and 30 to th ber of closely succeeding alternatingcurrent impulses over the phantom circuitfone impulse being transmitted foreach actuation4 of the ke and another impulse of reversed polarity in transmitted for the release of such key. guch impulses flowing through at. station4 B cause the selector to advance step-by-step until it reachesA its individually selective position, in which` it is mechanically retained. Other selectors,

not shown, also advance in response to such impulses but not being adjusted for the comconsequently not retained, upon the cessation of the .series for selecting station B. Relay 14 is thereupon operated over the circuit established from one side of battery through one normal contact of relay 2 the side circuit relay 14. The actuation of key 17 at ther observers station thereupon supplies current to the physical line circuits 3 4 and 5 6 through retardation coils 18 and 19, respectively, so that the current varying devices of detectors 15 and 16 cause variations in the current in such physical circuits in response to the vibrations of the responsive members of the detectors. The characteristics of the simple'xing coils and the other apparatus bridged across the physical circuits are so chosen as to prevent no material interference to the transmission of such eurrent variations.

ese current variations are transmitted through condensers 23 and 24 to receivers 21 and 22 respectively, of the binaural observation set 20. The sounds being produced by receiver 2l in response thereto are contubes 25, 27 and 29 to the ear plece 31, while the sounds produced by receiver 22 are conveyed through the air e ear piece 32. The movable stop-member 33 is then shifted by means of a hand wheel 34 until the observer, upon listening binaurally to the sounds emitted by the ear pieces, receives the impression that the source of sound is straight ahead. The position of the ointer 35, relative to the associated scale w en such an impression is obtained, indicates the angularA the other side ofrelation of the observed source of vibration to a base line joining detectors 15 and 16.l

he operating circuit of detector 16 is represented by Fig. 2, all unnecessary apparatus and circuit connections being removed therefrom.I

In case additional selecting impulses are phantom circuit while the detector 16 is operatively associatedwith 'the line conductors 5 and 6 by the simultaneous closure of both alternate contacts of relay 2, no unbalance should result in the current flowing over conductors 5 and 6 and no momentary surge of current would result. However, in case one ,of the altercurrent supplied through such contact would charge the condensers 42 to 47, inclusive, such current assuming the wave form represented by curve X of Fig. 3. If the capacitances of certain of the condensers are slightly unequal, as would frequently happen at different times, there associated resistance 50 to ground. However, due to the well-known retarding effect of an impedance windin such as the 95 windings 38, 39, 40 and 41 of tige coils 36 and 37, the current wave would be caused to asthe form shown by curve Y of Fig. 3 upon passing through the impedance winding of the coil 36 or 37. Therefore, the va- 10o riations in the current passin through the detector 16 would be more gra ual and would not cause the phenomenon known as coher- -mg. The same action would take place in connection with the circuit for the detector 15 which would be similar to that shown for detector` 16 in Fig. 2.

Due to the fact that as to mutually balance each other, it is evident that no impedance is introduced in the normal operating circuit of the 'detectors 15 and 16. l 115 What is claimed is:

In a transmission line, a pair of conductors, one of which has a capacitance to a grounded connection, a transmitter elec-y trically connected .to said conductors, and means connected in the line immediately adjacent the transmitter for preventing packing of the transmitter due to' surges on the other of said conductors.

2. In atransmission line, a pair vof conductors, each having a capacitance to a grounded connection, a transmitter electrically connected to said, conductors, and a pair of impedance windings connected to the conductors immediately adjacentv the transmitter tov prevent packing of the transmitter due to surges on the line. Y

3. In a transmission line, a pair of conductors, each having a capacitance to a grounded connectioma transmitter containing comminuted resistance varying material electrically connected to said conductors, and means inserted in the line adjacent to and on either side of said transmitter to modify the wave front of surges occurring on the line thereby preventing packing of the comminuted material.

4. In a transmission line, a pair of conductors, each having a capacitance to a grounded connection, a transmitter containing comminuted resistance varying material electrically connected to the line, a source of current, means for connecting said source of current to the line, and means for modifying the wave front of surges resulting from the discharge of said capacitances whereby packing of the comminuted material is prevente 5. In a transmission system', a metallic line comprising a pair of conductors, one of which has a capacitance to a grounded connection, a source of current bridged across the line circuit, a receiver and a transmitter intensa also bridged across the line circuit at separate oints, means for impressing a current impu se upon the other conductor of the line circuit from a separate source whereby such capacitance is charged through the transmitter, and means interposedl between `the second mentioned conductor and the transmitter to retard the fiow of charging. current through the transmitter.

6. In a transmission line, a receiver, a transmitter containing comminuted resistance varying material, a pair of conductors interconnecting said receiver and transmitter, each,y of said conductors having a capacitance to a grounded connection, a source o current associated with the conductors, and an impedance coil having a pair of inductively balanced windings, ings being included in each conductor 1mmediately adjacent the transmitter' to present high impedance to currents flowing over both conductors of the line circuit in parallel, and to present substantially no impedance to currents fiowing over such conductors in series.

In witness whereof, l hereunto subscribe my name this 17th day of June, A. D. 1919.

DAVID G. BLATTNER.

one of such wind- 

